An American soldier photographs a man arrested outside the Dand district command centre by Afghan police. The containers recovered from his vehicle were believed to contain explosives used for making IEDs

As the marines of 40 Commando return from Afghanistan's deadly Sangin province Sean Smith's brutal, uncompromising film from Helmand's frontline shows the horrific chaos of a stalemate that is taking its toll in blood

Guardian film-maker and photographer Sean Smith has just spent five weeks in Afghanistan, first with a US helicopter ambulance crew, and then with the US marines. This is his astonishing diary of his time with special forces